The planes are highly magical places. Whereas most magic functions as intended on the Prime Material, when traveling to other planes, the nature of the planes often strongly alters the usage of magic there. An unaware spell caster could find herself in deep peril should one of her spells go off in a way unintended. Experienced spellcasters know to see out spell keys (which could be an adventure in itself) when they need to travel across the planes.

In General
Spells with an alignment or energy descriptor that matches the that of it's plane are Empowered, Widened, Enlarged, and Extended where appropriate. Spells with descriptors that oppose the planes alignment are Impeded. Planeshifting from an Outer Plane to an Inner Plane (and vice-versa) causes the spell to become impeded. When creating a magic item with a descriptor that matches the plane it's on, (Example: Celestial armor on the upper planes, Axiomatic weapons on lawful planes, Flaming swords on the plane of fire, ect.) all time, XP and GP costs are reduced by 50%. Additionally, most planes have spell keys which a caster can seek out to allow their spells to function as normal. Finally, any of these traits are subject to change within the realm of a power.

Additional Rules

As skills are easy to boost, Impeded spells now require a DC20+spell-level caster level check to succeed.

AcheronGeneral
When a spell is cast, a spell crystal goes fly off at a rate of 100ft./round. This crystal can be caught and if used, will undo any effects of the spell. The crystal lasts for 1 hour/spell level.

Conjuration
When calling a creature (through planar binding/ally/gate ect.) the caster must supply a petitioner or sentient creature not native to the prime in it's place, who takes the place of the called creature on it's home plane until the spell ends. The victim is entitled to a will save (spells DC) to resist. If the save is successful, the caster must also save or be taken by the spell. The control of the spell is then given over to the former victim. If both saves succeed then the spell fails. Creatures bound suffer a -3 penalty to their charisma checks to resist being bound, and will work for half the usual price.

Divination
Scrying may not be used to gain information on opposing armies or forces. Auguries (and similar spells like Foresight) have their information apply to the entire group one belongs to.

Necromancy
Armies are easy to obtain on Acheron. There are no limits to how many undead one may control while on Acheron. If the controller leaves the plane, their control limits return, and they must release undead from their control until they are within their limits. Returning to the plane doesn't bring back control of these creatures.

Other
Water and Fire spells are Empowered, Widened and Enlarged. Earth spells are impeded. Beneath the surface of a cube, Air spells are impeded. Fire magic affects the iron of the cubes like a heat metal at searing heat (2d4 damage) in the spells area for a number of rounds equal to the caster level.

Other Effects:
* Creatures with a Command Rating have that rating rise by 2.
* War and aggression are inherent to Acheron. Diplomacy checks to improve the attitude of a creature suffer a -5 penalty.
* Creatures receive a +3 bonus to damage rolls.

Conjuration
If a non-evil creature is called for a noble cause or to benefit the greater good, it is automatically friendly towards the caster and will work for half the usual price. If called for selfish or evil reasons, the creature recieves +4 on it's opposed charisma checks.

Divination
Scrying and other divinations may only be used to gather information on groups of four creatures or more. Anything smaller and the spell fails.

Enchantment
Native animals are immune to mind-affecting effects. All other creatures gain a +3 bonus to saves against such effects. If the victim makes the save, the caster must save against the same spell or fall under the control of the initial target as if they had cast the spell.

Illusion
Illusions are automatically disbelieved by a native of the plane unless the caster is of a higher CR than them. Other creatures receive +3 to saves to disbelieve once they interact with the illusion.

Evocation
For casters of Lawful Good and Lawful Neutral alignment, spells that deal damage are Maximized, Widened and Enlarged. For casters of chaotic alignment, such effects are impeded.

Baator

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Conjuration
Summoned creatures are not under the control of the caster and may act freely until the spell ends. They typically start out indifferent to the caster unless they are opposed in alignment in which case they are unfriendly. Summoning and calling spells take one step longer to cast (refer to Arcadia). The caster recieves -3 on opposed charisma checks against bound creatures.

Divinations
Answers to spells like Commune and Contact Other Plane are typically given in the worst light possible. Additionally, the casting of a Divination spell has a 25% chance of alerting all devils within 1 mile of the spell being cast and the casters location.

Necromancy
Healing spells are Impeded, while spells that manipulate negative energy are Empowered and gain a +1 bonus to caster level.

Evocation
Cold and water spells are Empowered, Widened, and Enlarged on Stygia while fire spells are impeded. The opposite is in effect on Avernus and Phlegethos (earth spells are also subject to these benefits on Avernus). Fire spells automatically fail on Caina while cold and air spells are Maximized, Widened and Enlarged.

Mechanus

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Conjuration
If a lawful creature is called it automatically obeys the caster if the caster is also lawful. Summoning spells are Extended if summoning a lawful creature Calling and summoning spells are Impeded if the caster or the creature is chaotic.

Divinations
Divinations cast by chaotic creatures are impeded.

Illusions
Illusion spells automatically fail on Mechanus.

Necromancy
Casting a spell of the necromancy school forces the caster to sacrifice hit points equal to 4x the level of the spell. (0-level spells cost 1hp).

Other
Air spells require the caster to breathe Mechanus's air to cast (treat as always requiring a verbal component. Earth spells require dirt native to Mechanus as a material component. Water spells likewise require water native to Mechanus as a material component, and the same goes for fire spells (a spark struck off of a cog is enough for this).

Celestia

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General
The following spells automatically fail on Celestia: Blur, Contagion, Confusion, Enervation, Misdirection, Demand, Trap the Soul. Also, casters suffer a 10% chance for their spells to fail for each step they are away from Lawful Good.

Conjuration
Good or Lawful called creatures will perform services for half the normal cost. Evil creatures may not be called (though summoning spells that bring evil creature are merely Impeded.

Necromancy
Spells which manipulate positive or negative energy are Maximized.

The Abyss

General
All spells have a 5% chance of going awry per level of the spell, instead causing a random effect. Any save DCs are the same as the original spells.

Abjuration
Such spells have a 25% chance of failing when they would otherwise protect against something. For example a Resist Fire failing against a source of fire damage.

Conjuration
There is a 10% chance per level of the spell that summoning and calling spells instead bring a demons with a CR equal to what was originally intended to arrive and who is usually hostile to the caster. In the case of a summoning, the creature is not under the casters control, and in the case of a calling, the binding automatcally fails.

Divination
If cast within the realm of a demon lord or power, the lord of the realm is automatically notified of the spell being cast and the casters location.

Evocation
Damaging spells are Empowered and inflict an extra point of damage per die.

Illusion
Illusion spells gain a +1 bonus to caster level and save DC.

Necromancy
If present, a caster can cause an adjacent petitioner or demon to enter the body a mindless undead they control and manipulate it as if by Magic Jar. Though intelligent, they are still under the necromancers control. Unwilling creatures may make a will save (10+1/2 casters HD+Highest mental ability modifier) to resist. Demons may use any spell-like abilities they possess through the undead. If the undead is slain, the demon is freed and appears in the same square as the undead.

Reincarnation has a 25% chance of instead bringing back the target as a demon of an equal CR.

Transmutaion
Spells that alter the form of a target (such as polymorph) have a 25% chance of the target gaining the half-fiend template instead. Such creatures lose all self-control and go on a mindless rampage, attacking the nearest creature to the best of their ability, until the spells duration ends or is dispelled. Spells that transform objects (Mending, Polymorph Any Object) have a similar chance to go awry, and instead create something unpleasant (maggots, slime, explosions, more demons) usually keyed to the layer.

Arborea

Conjuration
Attempting to summon or call an evil creature has a 75% chance to alert all Eladrin within 10 miles to the spell being cast, the creature being called, and the casters location.

Divination
Such spells require props to use, for example Auguries require sacrifices and are read in entrails. Scrying spells require pools of clear waters. Foresight requires one to read the stars ect. Also, the casting time of such spells is increased by 1 round per level of the spell.

Enchantment
All spells and effects that manipulate emotions (Example: Charm, Hope, Fear, Heroism, Rage, Despair, ect.) gain +4 to their save DCs and their durations are doubled. However, should the target roll a natural 1 on the save, they instead attack the caster in a berserk rage for 1 minute.

Illusion
All spells of this school are Empowered, Widened, Enlarged, and Extended where applicable. They gain +4 to their DC. True seeing doesn't automatically see through them, and instead grants them an immediate save to disbelieve. If they fail, they are stuck believing the illusion until a save would normally be called for.

Other
Air spells are Empowered, Widened, Enlarged and Extended on Arvandor, Water spells revieve the same benefit on Aqualor, and Earth spells likewise on Mithardir. Spells which manipulate plants receive the same benefits anywhere on Arborea.

Limbo

In General
All spells cast on Limbo have a 10% chance per spell level of instead creating a random effect. Any save use the original spells DC. Slaadi are unaffected by this unless they wish to. Open ended spells, such as Wish, Limited Wish, Miracle, and Reality Revision have a greater chance of going awry.

Divination
Such spells have a 25% chance of having the results be so incoherent that the caster receives no information.

Evocation
Energy spells are Empowered, Widened, Enlarged and Extended. Spells with an instantaneous duration instead fill their areas for 1d6 rounds, affecting any creature in that area. Spells with single targets fill the square of their target for the duration.

Illusion
Shadow Illusions are 10% more real.

Transmutation
Spells which change a creatures appearance (such as polymorph) have a 25% chance to instead transfrom the target into some other creature. (Roll on a random encounter chart.) If the spell's duration expires, is dispelled or the creature is slain, it reverts back to it's normal form, unharmed.

GeneralFly (and similar spells) fail automatically. Only creatures able to fly naturally (without the aid of magic) can do so here (though transforming into a form that can fly naturally will work).

Conjuration
Creatures summoned or called are under no compulsion to follow the casters orders. Additionally, summoning spells may only call animals or magical beasts.

Divination
All divinations that deal with other planes (scrying on other planes, contact other plane, sending messages to other planes) automatically fail.

Enchantment
Animals and Magical Beasts on the Beastlands are immune to mind-affecting effects.

Evocation
All fires burn twice as hot on Krigala (the first layer) dealing twice as much damage. Additionally, fire spells are Widened, Enlarged, and Extended. On Karasuthra fires burn weaker, dealing half as much damage, additionally, fire spells are Impeded.

Water, Cold, Air, and Earth spells are Widened, Empowered, Enlarged and Extended, as are spells which manipulate the weather.

Spells which create light are Impeded on Karasuthra, and even if successful only shed half as much light. Even natural light sources other than Noctos are halved here.

Necromancy
All spells of this school are impeded and suffer a -1 penalty to caster level per layer of the plane.

Bytopia

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General
Change is rare on Bytopia. Spells which enact large scale changes (control weather, control water, earthquake, fimblewinter,) are Impeded.

Conjuration
Creation spells can only create objects that exist naturally on the plane.

Conjuration
Summoned creatures are not under the casters control, and are free to do as they wish until the spells duration expires or they are banished.

Enchantment
Mind-Affecting effects automatically fail when used on a native of the plane. Good aligned visitors to the plane recieve +4 to their saves against mind-affecting effects. Spells which create positive emotions (Charm, Hope, Heroism) have their durations doubled (and the bonus to saves doesn't apply to Charm effects). Additionally, spells which create negative emotions (Rage, Despair, Fear) are impeded, if successful have their durations halved and 50% likely to alert any guardinals within 1 mile to the spell being cast and the casters location. Crushing Despair has a 100% chance of alerting a Guardinal.

Evocation
Water spells are Empowered, Extended, Widened, and Enlarged on Thalasia.

Necromancy
Spells which maniuplate negative energy automacally fail, and there's a 33% chance that such a spell backfires and affects the caster.

CarceriI couldn't find a picture I liked, so instead, here's one of a flying shark.

Conjuration
Summoned creatures are not under the casters control, and are free to do as they wish until the spells duration expires or they are banished or slain. However, inversely, called creatures bound in a magic circle suffer -4 to charisma checks against the caster of the spell.

Divination
Any scrying or augury like spell requires the sacrifice of a comrade to function. The spell takes shape in the victims pooling blood.

Enchantment
Targets suffer a -4 penalty to save against mind-affecting abilities, though if they successfully save, they are immune to further attempts from that creature for 1 hour.

Necromancy
Spells which manipulate positive energy are impeded, and even if successful only function at half power.

Gehenna

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Conjuration
Calling spells, inversely, may only call creatures native to the plane. The caster receives -4 to his opposed charisma checks. Should the charisma check fail the bound creature automatically breaks free.

Divination
Scrying spells and other spells such as Augury and Contact other Plane require the caster to torture a sapient creature for the duration of the spell.

Evocation
Damaging spells are cast at a level higher, are Empowered, Enlarged and Widened, and gain +1 to save DCs.

Necromancy
Spells that manipulate positive energy suffer a -1 penalty to level. Spells that maniuplate negative energy have +1 to caster level (+2 on Krangath). Spells that create undead gain an additional +1 to caster level, Rebuking Undead works as if the user were a level higher and Turning Undead works as if the user were a level lower.

Other
Fire and Earth spells gain +2 to caster level on the first three layers (Khalas, Chamada, and Mungoth). Water spells automatically fail on the second and third layer. Cold spells are Empowered, Widened, Enlarged and Extended on the third layer. Fire spells automatically fail on the fourth layer.

Conjuration
Summoned creatures are not under the command of the summoner and are free to act as they wish until the spells that brought them has it's duration expires. They start out indifferent to the caster, unless they have opposing alignments, in which case they are hostile.

Divinations
All divinations spells have a 50% chance of giving false information.

Enchantment
Spells which create positive emotion (Charm, Hope, Heroism) are impeded, and have a 50% chance of alerting all Yugoloth of the plane within 10 miles to the spell being cast and the casters location. Also such spells suffer a -3 penalty to their save DCs and caster level. Additionally, Good Hope has a 100% chance of alerting a native. Spells which create negative emotions (Rage, Despair, Fear) recieve +3 to save DC's and are Extended.

NecromancyAnimate Dead gains the ability to create Ghouls.
All spells that maniuplate positive energy fail automatically. All necromancy used by Good creatures has a 33% chance to backfire and affect the caster instead.

Other Effects:

* The Grays: This Grays spiritual corruption that affects any creature that is not a fiend, weighing down upon their very soul the longer they spend on the plane. At the end of 24 hours spent on the plane, a creature with a soul must make a DC20 will save or suffer a point of wisdom and charisma damage. Regardless of save success or failure, they must continue to make saves every 12 hours after that. This bypasses any immunity to ability damage or drain they may possess. The damage cannot be healed by anything short of a wish or miracle until they leave the plane. There are save zones on the plane, where the timer doesn't progress, but any damage or drain incurred still doesn't heal.
* Greyscale Colors are muted on the plane. Everything appears in black

The Outlands

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General
The spire in the center of the plane reduces magic the closer one approaches it. Refer to the chart.

There are no known spell keys or abilities to avoid this effect, although Rilmani, Aeons, and Tuladhara, are unaffected by the spire.

Conjuration
All spells that call or summon creatures from planes other than the outer planes or the astral are impeded. All spells that allow travel to or from a plane other than the outer planes or the astral are impeded.

Divination
Spells which contact or scry upon creatures or locations not in the outer planes or that astral are impeded.

Sigil

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Conjuration
Spells that allow planar travel (teleport, gate, shadow walk, etherealness, dimension door, planeshift, ect.) automatically fail when used to travel into, out of, or within Sigil. Summoning and Calling spells automatically fail as well. There are no known spell keys to avoid this.

Divination
Scrying automatically fails within Sigil, as does Contact Other Plane. There are no known spell keys to avoid this.

Other
Gods are banned from Sigil. Any creature that either has divine ranks or is a non native outsider or elemental with a CR above 20 may not enter through any portal into Sigil. They are also subject to all of Sigils other effects.

Notes: So I was flipping the Planescape source books, and I realized that back then, the planes had all sorts of ways of fucking with your magic. The vast majority of this was conspicuously absent from third edition. As I like to run planar campaigns, I figured these could be good ways to spice up the planes.

I've updated these to third edition, removed some stupid things (like summon monster I being able to net you a Pit Fiend on Hades) or things that were DM arbitrated (like being able decide that your protective spells failed on the abyss whenever he damn well felt like it). And added some of my own as well.

Please tell me if you have and questions, concerns, or ideas.
~Wiseman_________________Check out my RP site!

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deaddmwalking wrote:

The more player input you allow, the more interesting the characters are going to be. The more interesting the characters, the more fun everyone at the table is going to have.

RadiantPhoenix wrote:

TheFlatline wrote:

Legolas/Robin Hood are myths that have completely unrealistic expectation of "uses a bow".

The D&D wizard is a work of fiction that has a completely unrealistic expectation of "uses a book".

hyzmarca wrote:

Well, Mario Mario comes from a blue collar background. He was a carpenter first, working at a construction site. Then a plumber. Then a demolitionist. Also, I'm not sure how strict Mushroom Kingdom's medical licensing requirements are. I don't think his MD is valid in New York.

Last edited by Wiseman on Wed Apr 19, 2017 6:49 am; edited 9 times in total

Man, I totally respect your work, specially as a huge Planescape fan that I am, but having to decorate how a dozen different spell types interact with a dozen different planes is the exact kind of thing I left behind a long ago in gaming and dont have the least desire to looking back.

These were steamlined from their original versions. Also, ideally, a planar adventure should generally be containted to one plane or maybe two (and possible sigil as a start/end point) so it shouldn't be hard to keep track of the magic traits for those planes.

EDIT: Also, players with ranks in Knowledge: (The Planes) (which any self-respecting planar traveller should have) should be made aware of this themselves, meaning the burden is not entirely on the DM._________________Check out my RP site!

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deaddmwalking wrote:

The more player input you allow, the more interesting the characters are going to be. The more interesting the characters, the more fun everyone at the table is going to have.

RadiantPhoenix wrote:

TheFlatline wrote:

Legolas/Robin Hood are myths that have completely unrealistic expectation of "uses a bow".

The D&D wizard is a work of fiction that has a completely unrealistic expectation of "uses a book".

hyzmarca wrote:

Well, Mario Mario comes from a blue collar background. He was a carpenter first, working at a construction site. Then a plumber. Then a demolitionist. Also, I'm not sure how strict Mushroom Kingdom's medical licensing requirements are. I don't think his MD is valid in New York.

Last edited by Wiseman on Fri May 30, 2014 4:43 pm; edited 1 time in total

Doing Away with the Ethereal
The ethereal plane makes very little sense in the planar cosmology of DND. In Planescape, it was the transitive plane that connected the prime to the inner planes, with the astral connecting to the outer. Despite the fact that the Outer Planes were the spiritual realms, where the dead manifested, ghosts were inexplicably tied to the ethereal. WTF?! That makes no goddamn sense. Or at least less sense than the normal planescape setup. Even I can't mind caulk this! The inner planes have no notable actual connection in that model to the outer planes normally without jumping through a ton of intermediary planes (don't get me started on the nonsense that was the Ordial plane.)

In third edition, the astral connects to everywhere in the multiverse and the ethereal does much the same according to the manual of the planes. At that point, what's the freaking difference? (either that or it just connects to the Prime material by default, but that's even worse.)

One of the few things 4e got right was the astral sea. It did away with the great wheel, and made all planes now float in the great sea. You could "sail" the astral sea, and end up in various other planes, (like say sailing into Celestia's silver sea or running aground on Minethys).

Working with this, we could do away with the ethereal plane as it exists in it's current form, and instead divide the astral into two segments, the Border Astral (aka the Ethereal) and the Deep Astral (aka the Astral Sea).

The Border Astral
The border astral (sometimes called Ethereal) is a location closely tied to a plane. It's where souls can manifest after death, and is potentially home to numerous strange entities. The Border Astral in general resembles area on the plane it corresponds to, though structures may be different. A fog is omnipresent, usually silver-white, though it can take a variety of colors if a being or beings in either the border region or the coterminous plane possess particularly strong emotion. Those who dwell on the Border Astral can look upon the coterminous plane, though the visage is somewhat distorted and blurry, and sounds are often muffled. Visibility is limited to 60ft normally. Creatures on the coterminous plane cannot observe the border region at all normally.

There are creatures who frequently reside her, mainly the fearsome Ethergaunts.

Planar Traits:
Gravity, Time, Size, Elemental, Energy, and Alignment traits all are the same as the parent plane.

The Deep Astral
The Deep Astral (More often called the Astral Sea) is the backdrop in which the entire multiverse exists. All planes are contained within it, and it's from this that spiritual realms known as Outer Planes are formed. The gods can shape this area, creating divine realms, while powerful magicians can also do similar things. Some transform areas of existing planes into their domains, others create new planes for themselves.

There are creatures that reside directly within the Astral, such as the Githyanki, the Buomman, and the ever terrifying Astral Dreadnought. Also occasionally encountered are the corpses of deities who lost faith. Some are recognizable from historical records, others are completely alien.

Planar Traits
Subjective Directional Gravity
Timeless. Age, hunger, thirst, poison, and natural healing are halted in the Astral Plane, though they resume functioning when the traveler leaves the Astral Plane.
Mildly neutral-aligned.
Enhanced magic. All spells, psionics, psi-like and spell-like abilities used within the Astral Plane may be employed as if they were improved by the Quicken Spell feat. Already quickened spells and spell-like abilities are unaffected, as are spells from magic items. Spells so quickened are still prepared and cast at their unmodified level._________________Check out my RP site!

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deaddmwalking wrote:

The more player input you allow, the more interesting the characters are going to be. The more interesting the characters, the more fun everyone at the table is going to have.

RadiantPhoenix wrote:

TheFlatline wrote:

Legolas/Robin Hood are myths that have completely unrealistic expectation of "uses a bow".

The D&D wizard is a work of fiction that has a completely unrealistic expectation of "uses a book".

hyzmarca wrote:

Well, Mario Mario comes from a blue collar background. He was a carpenter first, working at a construction site. Then a plumber. Then a demolitionist. Also, I'm not sure how strict Mushroom Kingdom's medical licensing requirements are. I don't think his MD is valid in New York.

Last edited by Wiseman on Tue Oct 03, 2017 5:50 am; edited 1 time in total